1. Field of the Invention
The present invention relates to an apparatus for and a method of recording data into a disc-like recording medium driven to spin at a constant speed.
2. Description of Related Art
The conventional apparatuses for recording data into a recording medium include one adapted to record data into sectors formed on a magnetooptic disc by regularly dividing concentric tracks on the disc circumferentially thereof, one adapted to record data into a magnetooptic disc at a constant frequency and a constant speed of disc spinning, and one adapted to record data into a phase-changing optical disc at a constant frequency and a constant speed of disc spinning.
The above-mentioned data recording apparatus adapted to record data into a magnetooptic disc having sectors formed thereon by regularly dividing concentric tracks circumferentially of the disc, adopts the well-known CLV (Constant Linear Velocity) method to attain a high surface density with a constant linear density by recording the data at a constant linear velocity. For recording data into a magnetooptic disc having wobbling data tracks, this data recording apparatus detects track wobbling modulated for data to be recorded onto all data tracks with a same linear density in order to record the data at a constant frequency.
On the other hand the above-mentioned data recording apparatus adapted to record data into a magnetooptic disc at a constant frequency and a constant speed of disc spinning adopts the well-known CAV (Constant Angular Velocity) method to record the data at a constant speed of disc spinning not only in the lead-in zone but in the lead-out zone on the magnetooptic disc.
The above-mentioned data recording apparatus adapted to record data into a phase-changing optical disc at a constant frequency and a constant speed of disc spinning, adopts the CAV method as in the data recording apparatus mentioned just above. This data recording apparatus is also adapted to generate a write frequency by detecting a fine clock mark in order to record the data.
In the above-mentioned data recording apparatus adopting the CAV method for data recording into a phase-changing optical disc, however, the linear density of recording on data tracks formed in the lead-out zone is lower than that on the data tracks in the lead-in zone since data is recorded at a constant speed of disc spinning and a constant frequency not only in the data tracks formed in the lead-in zone but also in the data tracks formed in the lead-in zone. Also, in a disc having track wobbles modulated for data to be recorded onto all data tracks with a same linear density, the CAV control is impossible for a quicker data access since it is necessary to lock write clocks precisely to the track wobbles.